X-ray CT scanner

Abstract

The rotary member carrying the X-ray radiation unfit and the X-ray detection unit and rotated around a subject is used as the rotor. The rotor is provided with a rotor core and a plurality of conductors connected to the core. The stator has at least one set of stator core and stator winding, the at least one set of stator core and stator winding being adapted to clamp the rotor and arranged at opposing positions. A three-phase AC current is supplied to the stator winding to generate a rotating magnetic field to rotate the rotor and thereby rotate the rotary member at high speed. Because the scan time can be reduced, the X-ray CT scanner can scan such moving organs as heart.

What is claimed is:  
     
       1. An X-ray CT scanner comprising: 
       an X-ray radiation means for radiating X-rays against a subject;  
       an X-ray detection means arranged at a position opposite the X-ray radiation means with respect to the subject;  
       an opening in which to put the subject;  
       a rotary member mounting at least the X-ray radiation means and the X-ray detection means and rotated around the subject;  
       a rotary drive means for rotating the rotary member; and  
       a frame for supporting the rotary member and the rotary drive means;  
       wherein information on the X-rays that have penetrated the subject and are detected by the X-ray detection means is processed to generate a cross-sectional image of the subject;  
       wherein the rotary drive means is constructed so that the rotary member is used as a rotor including a rotor core and a plurality of conductors connected to the rotor core with at least one set of stators comprising a stator core and stator winding provided around a part of the rotor and includes a first stator member arranged at an opening side of the rotor and a second stator member disposed at an opposing position via the rotor with respect to the first stator member, and  
       wherein a three-phase AC current is passed through the stator winding to generate a rotating magnetic field between the first and second stator members to rotate the rotor and thereby the rotary member is rotated.  
     
     
       2. The X-ray CT scanner according to  claim 1 , wherein the rotor includes the rotor core made of a magnetic metal, first and second short-circuit rings and a plurality of conductors connected to the first and second short-circuit rings. 
     
     
       3. The X-ray CT scanner according to  claim 2 , wherein the rotor core is formed by laminating silicon steel plates punched with a plurality of slots, the conductors are installed in the plurality of slots, and the ends of the conductors are connected to the short-circuit rings. 
     
     
       4. The X-ray CT scanner according to  claim 1 , wherein when a plurality of stators are provided, they are arranged at almost equal intervals in the circumferential direction of the rotor. 
     
     
       5. An X-ray CT scanner comprising: 
       an X-ray radiation means for radiating X-rays against a subject;  
       an X-ray detection means arranged at a position opposite the X-ray radiation means with respect to the subject;  
       an opening in which to put the subject;  
       a rotary member mounting at least the X-ray radiation means and the X-ray detection means and rotated around the subject;  
       a rotary drive means for rotating the rotary member; and  
       a frame for supporting the rotary member and the rotary drive means;  
       wherein information on the X-rays that have penetrated the subject and are detected by the X-ray detection means is processed to generate a cross-sectional image of the subject;  
       wherein the rotary drive means is constructed so that the rotary member is used as a rotor includes a magnetic metal body and conductors connected to both surfaces of the magnetic metal body, and at least one set of stators comprising a stator core and stator winding located at opposing positions over both sides of the rotor and includes a first stator member and a second stator member which are arranged at opposing positions via the rotor and  
       wherein a three-phase AC current is passed through the stator winding to generate a rotating magnetic field between the first and second stator members to rotate the rotor and the rotary member is rotated.  
     
     
       6. The X-ray CT scanner according to  claim 5 , wherein the rotor core is formed by fixing plate conductors to both surfaces of the magnetic metal body. 
     
     
       7. The X-ray CT scanner according to  claim 5 , wherein when a plurality of stators are provided, they are arranged at almost equal intervals in the circumferential direction of the rotor. 
     
     
       8. An X-ray CT scanner comprising: 
       an X-ray radiation means for radiating X-rays against a subject;  
       an X-ray detection means arranged at a position opposite the X-ray radiation means with respect to the subject;  
       an opening in which the subject is positioned;  
       a rotary member mounting at least the X-ray radiation means and the X-ray detection means and rotated around the subject;  
       a rotary drive means for rotating the rotary member; and  
       a frame for supporting the rotary member and the rotary drive means;  
       wherein information on the X-rays that have penetrated the subject and are detected by the X-ray detection means is processed to generate a cross-sectional image of the subject;  
       wherein the rotary drive means is constructed so that the rotary member is used as a rotor, and that at least one set of stators is provided around a part of the rotor and comprises a first stator member arranged at an opening side of the rotor and a second stator member arranged at an opposing position via the rotor with respect to the first stator, and  
       wherein a three-phase AC current is passed through the one set of stators to generate a rotating magnetic field between the first and second stator members to rotate the rotor and thereby the rotary member is rotated.  
     
     
       9. An X-ray CT scanner comprising: 
       an X-ray radiation means for radiating X-rays against a subject;  
       an X-ray detection means arranged at a position opposite the X-ray radiation means with respect to the subject;  
       an opening in which the subject is positioned;  
       a rotary member mounting at least the X-ray radiation means and the X-ray detection means and rotated around the subject;  
       a rotary drive means for rotating the rotary member; and  
       a frame for supporting the rotary member and the rotary drive means;  
       wherein information on the X-rays that have penetrated the subject and are detected by the X-ray detection means is processed to generate a cross-sectional image of the subject;  
       wherein the rotary drive means is constructed so that the rotary member is used as a rotor, and that at least one set of stators is provided so as to sandwich a part of the rotor by an inner circumferential stator and an outer circumferential stator which are arranged in an order of inner circumference stator, rotor and outer circumferential stator from a center of the opening of the rotor in a radial direction; and  
       wherein a three-phase AC current is passed through the one set of stators to generate a rotating magnetic field between the inner circumferential stator and outer circumferential stator to rotate the rotor and thereby the rotary member is rotated.  
     
     
       10. The X-ray CT scanner according to  claim 9 , wherein the rotor comprises the rotor core made of a magnetic metal, two short-circuit rings provided in a direction of a rotating axis and a plurality of conductors connected to the short-circuit rings. 
     
     
       11. An X-ray CT scanner comprising: 
       an X-ray radiation means for radiating X-rays against a subject;  
       an X-ray detection means arranged at a position opposite the X-ray radiation means with respect to the subject;  
       an opening in which the subject is positioned;  
       a rotary member mounting at least the X-ray radiation means and the x-ray detection means and rotated around the subject;  
       a rotary drive means for rotating the rotary member; and  
       a frame for supporting the rotary member and the rotary drive means;  
       wherein information on the X-rays that have penetrated the subject and are detected by the X-ray detection means is processed to generate a cross-sectional image of the subject;  
       wherein the rotary drive means is constructed so that the rotary member is used as a rotor, and that at least one set of stators is arranged around a part of the rotor and comprises a first stator member arranged over one side of a rotation plane of the rotor and a second stator member arranged over an other side of the rotation plane, the second stator member being positioned at an opposing position with respect to the first stator member, and  
       wherein a three-phase AC current is passed through the one set of stators to generate a rotating magnetic field between the first and second stator members to rotate the rotor and thereby the rotary member is rotated.  
     
     
       12. The X-ray CT scanner according to  claim 11 , wherein the rotor comprises a rotor core having two short-circuit rings of different diameter and a plurality of conductors connected to both ends of the short-circuit rings. 
     
     
       13. The X-ray CT scanner according to  claim 11 , wherein the rotor core is formed with a magnetic metal body and plate conductors connected to both surfaces of the magnetic metal body. 
     
     
       14. An X-ray CT scanner comprising: 
       an X-ray radiation means for radiating X-rays against a subject;  
       an X-ray detection means arranged at a position opposite the X-ray radiation means with respect to the subject;  
       an opening in which the subject is positioned;  
       a rotary member mounting at least the X-ray radiation means and the X-ray detection means and rotated around the subject;  
       a rotary drive means for rotating the rotary member; and  
       a frame for supporting the rotary member and  
       the rotary drive means;  
       wherein information on the X-rays that have penetrated the subject and are detected by the X-ray detection means is processed to generate a cross-sectional image of the subject;  
       wherein the rotary drive means is constructed so that the rotary member is used as a rotor, and that at least one set of stators including a stator over one side of the rotor and another stator over an other side of the rotor is provided so as to sandwich a part of the rotor in a direction of a rotating axis of the rotor, and  
       wherein, a three-phase AC current is passed through the one set of stators to generate a rotating magnetic field between the first and second stators to rotate the rotor and thereby the rotary member is rotated.  
     
     
       15. The X-ray CT scanner according to  claim 14 , wherein the rotor comprises a rotor core having two short-circuit rings of different diameter and a plurality of conductors connected to both ends of the short-circuit rings.